Patients with early-stage HER2-positive breast cancer should still receive 1 year of adjuvant trastuzumab as the standard of care, according to data from the phase III HERA trial. HERA compared the efficacy and safety of 1 year and 2 years of treatment.

“Giving trastuzumab for a longer duration (2 years) did not improve disease-free or overall survival compared with 1 year of trastuzumab treatment,” said Martine J. Piccart, MD, PhD, and chair of the Breast International Group (BIG). Piccart presented these results at the 2012 CTRC-AACR San Antonio Breast Cancer Symposium, held December 4-8, 2012.

The HERA trial was an international, multicenter, phase III, randomized trial conducted by BIG and Roche. The trial followed 5,102 women with early-stage HER2-positive breast cancer who were randomly assigned to trastuzumab every 3 weeks for 1 or 2 years, or to observation. All women completed a primary therapy of surgery, chemotherapy, and radiotherapy, as indicated.

Both disease-free status and overall survival rates were comparable between the 1- and 2-year trastuzumab arms. Additionally, while the primary cardiac end point of symptomatic congestive heart failure was comparable in both arms, the 2-year arm had a higher rate of the secondary cardiac end point of asymptomatic cardiac dysfunction at 7.2% compared with the 1-year arm at 4.1%. Most cardiac events occurred during trastuzumab administration, and were reversible when the trastuzumab was stopped.

“The HERA trial showed the sustainability of the efficacy of trastuzumab, proving that a significant proportion of patients treated with trastuzumab in the adjuvant setting are alive and free of disease recurrence after a median follow-up of 8 years,” Piccart said. “It is also reassuring with regard to the low cardiac toxicity of trastuzumab when given after adjuvant chemotherapy. Finally, it confirms that 1 year of adjuvant trastuzuamb should remain the standard of care in women with early-stage HER2-positive breast cancer.”